Data storage devices store and retrieve large amounts of computerized data in a fast and efficient manner. Such devices may include one or more data storage discs that are rotated by a spindle motor at a constant high speed. Data transfers with tracks on the discs are carried out using a rotary actuator assembly (also referred to as a head stack assembly, or HSA). The HSA supports a corresponding number of data transducing heads that are controllably moved across the disc surfaces by an actuator motor (also referred to as a voice coil motor, or VCM).
The spindle motor and the HSA are typically mounted to a base deck that cooperates with a top cover to provide a protected interior environment for the discs and heads. A printed circuit cable (PCC) provides the requisite electrical communication paths between the HSA and a disc drive printed circuit board (PCB) mounted to the exterior of the base deck. The disc drive PCB supports communication and control electronics for operation and control of the disc drive.
The printed circuit cable (PCC) includes a flex cable that has a flexible, laminated member that electrically isolates and supports a number of embedded electrical conduction paths (conductors) along the length of the laminated member. One end of the flex cable is supported by a flex cable support (also referred to as a flex cable clamp) that is mounted on the base deck; the distal end of the flex cable is attached to the HSA. Typically, a bulkhead connector extends through the base deck to facilitate electrical connection from the flex cable support to the disc drive PCB.
The intermediary portion of the flex cable between the flex cable support and the HSA is a dynamic slack loop that provides strain relief while the HSA moves the heads across the full radius of the disc surfaces. In practice, the flex cable loop acts as a spring that exerts undesired bias force on the HSA as the heads are moved to different radial positions with respect to the disc surfaces. This bias force tends to nominally urge the heads away from the desired position over a selected track, so this bias force must be within a range that is compensated by servo control circuitry of the drive to assure that the disc drive operates predictably.
A disc drive design must provide printed circuit cable (PCC) configurations with controllable and repeatable flex cable dynamic loop characteristics over the desired range of HSA motion. Furthermore, there is a continuing trend to improve not only disc drive operational characteristics, but also to improve disc drive manufacturing processes. Top down assembly (unidirectional positioning and installation of components in the disc drive) has become the ultimate goal in creating low cost disc drives. It is to such improvements that the claimed invention is directed.